A switch-mode power converter (also referred to as a “power converter” or “regulator”) is a power supply or power processing circuit that converts an input voltage waveform into a specified output voltage waveform. DC-DC power converters convert a dc input voltage into a dc output voltage. Controllers associated with the power converters manage an operation thereof by controlling the conduction periods of power switches employed therein. Controllers generally control a power switch of the power converter to enable its power conversion function. Controllers may be coupled between an input and output of the power converter in a feedback loop configuration (also referred to as a “control loop” or “closed control loop”) to regulate an output characteristic (e.g., an output voltage, an output current, or a combination of an output voltage and an output current) of the power converter.
In an exemplary application, the power converter has the capability to convert an input voltage (e.g., 2.5 volts) supplied by an input voltage source to a lower, output voltage (e.g., 1.25 volts) to power a load. To provide the voltage conversion functions, the power converter includes active power switches such as metal-oxide semiconductor field-effect transistors (“MOSFETs”) that are coupled to the input voltage source and periodically switch the active power switches at a switching frequency “fs” that may be on the order of one megahertz (“MHz”) or greater.
In typical applications of dc-dc power converters, power conversion efficiency is an important parameter that directly affects the physical size of the end product, its cost and market acceptance. The active power switches that are either fully on with low forward voltage drop or fully off with minimal leakage current provide a recognized advantage for power conversion efficiency in comparison with previous designs that utilized a dissipative “pass” transistor to regulate an output characteristic or a passive diode to provide a rectification function. Previous designs using pass transistors and passive diodes produced operating power conversion efficiencies of roughly 40-70% in many applications. The use of active power switches in many recent power converter designs, particularly as synchronous rectifiers for low output voltages, has increased operating efficiency at full rated load to 90% or more.
Functional electronic plug-in modules such as single- and dual-in-line memory modules (“SIMMs” and“DIMMs”) are commonly used to combine a number of chips, such as digital random-access memory (“DRAM”), to form a functional unit such as a memory module in common electronic applications. The standardized physical dimension (height, length and width) and the limited power handling capability of a memory module such as a DIMM card has thus far prohibited the placement of any power handling or conditioning supply on the DIMM card. Therefore, the memory modules such as DIMM cards reside on a motherboard, each with a DIMM card-to-motherboard connector therebetween. This design has several drawbacks including power losses associated with the connector due to high currents conducted through the connector at low voltages. Another drawback is the additional cost resulting from the need to pre-populate the motherboard with a power converter with a sufficient power rating to provide power for the maximum amount of memory that may be installed in an electronic system (e.g., computer) employing the same. The result is the inefficient deployment and utilization of power conversion resources, which has presented a long-standing and unaddressed industry need.
Thus, the problem of providing power for a plug-in module such as a DIMM card with efficient utilization of material and energy resources still remains an unresolved issue. Accordingly, what is needed in the art is a power converter and related method to provide a substantially regulated voltage for a module such as a DIMM card that overcomes deficiencies in the prior art.